The sea is characterised by its warm and stabwe cwimate[citation needed], wif freqwent rains and tropicaw cycwones. It contains numerous iswands and reefs, as weww as de worwd's wargest reef system, de Great Barrier Reef (GBR), which was decwared a Worwd Heritage Site by UNESCO in 1981. Aww previous oiw expworation projects were terminated at de GBR in 1975, and fishing is restricted in many areas. The reefs and iswands of de Coraw Sea are particuwarwy rich in birds and aqwatic wife and are a popuwar tourist destination, bof nationawwy and internationawwy.

The Coraw Sea basin was formed between 58 miwwion and 48 miwwion years ago when de Queenswand continentaw shewf was upwifted, forming de Great Dividing Range, and continentaw bwocks subsided at de same time.[4] The sea has been an important source of coraw for de Great Barrier Reef, bof during its formation and after sea wevew wowering.[5]

The geowogicaw formation processes are stiww proceeding, as partwy evidenced by de seismic activity. Severaw hundred eardqwakes wif de magnitude between 2 and 6 were recorded in de period 1866–2000 awong de Queenswand coast and in de Coraw Sea.[6] On 2 Apriw 2007, de Sowomon Iswands were struck by a major eardqwake fowwowed by a severaw metres taww tsunami. The epicentre of dis magnitude 8.1 eardqwake was 349 km (217 mi) nordwest of Honiara, at a depf of 10 kiwometres (6.2 mi).[7] It was fowwowed by more dan 44 aftershocks of a magnitude 5.0 or greater. The resuwting tsunami kiwwed at weast 52 peopwe and destroyed more dan 900 homes.[8]

The sea received its name because of its numerous coraw formations. They incwude de GBR, which extends about 2,000 km (1,200 mi) awong de nordeast coast of Austrawia and incwudes approximatewy 2,900 individuaw reefs[9] and 1000 iswands.[10] The Chesterfiewd Iswands and Lihou Reef are de wargest atowws of de Coraw Sea.

Major Coraw Sea currents form a counter-cwockwise gyro which incwudes de East Austrawian Current. It brings warm nutrient-poor waters from de Coraw Sea down de east coast of Austrawia to de coow waters of de Tasman Sea. This current is de strongest awong de Austrawian coasts and transforms 30 miwwion m3/s of water widin a fwow band of about 100 kiwometres wide and 500 metres deep. The current is strongest around February and weakest around August.[11]

The major river fwowing into de sea is de Burdekin River, which has its dewta soudeast of Townsviwwe. Owing to de seasonaw and annuaw variations in occurrence of cycwones and in precipitation (typicawwy between 200 and 1600 mm/year), its annuaw discharge can vary more dan 10 times between de two succeeding years. In particuwar, in de period 1920–1999, de average fwow rate near de dewta was bewow 1000 m3/s in 1923, 1931, 1939, 1969, 1982, 1985, 1987, 1993 and 1995; it was above 25,000 m3/s in 1927, 1940, 1946, 1950, 1951, 1959, 1968, 1972, 1974 and 1991, and reached about 40,000 m3/s in 1946.[12] This irreguwarity resuwts in concomitant fwuctuations of de sea water composition near de river dewta.

The surface water temperature varies on de souf of de sea from 19 °C in August to 24 °C in February. It is rader warm and stabwe at 27–28 °С in de norf aww drough de year. Water sawinity is 34.5–35.5‰ (parts per dousand).[1] The water is mostwy very cwear, wif de visibiwity of about 30 metres (100 ft) near de reefs.[9]

The sea has a subtropicaw cwimate and is freqwentwy hit by tropicaw cycwones, especiawwy between January and Apriw.[2] This range extends to November–May in de areas souf to 10°S. Between 1969 and 1997, de GBR experienced 80 cycwones, 90% which were of category 1 or 2 (winds 17–33 m/s, centraw pressure 970–1000 hPa) and onwy 10% of category 3 (winds >33 m/s, pressure <970 hPa). The cycwone freqwency decreased between 1997 and 2005 to 1.5 per year (12 in totaw).[13]

Annuaw rainfaww typicawwy ranges between 1,000 and 3,000 mm depending on de area. Most rains faww between December and March, in bursts of 30–60 days.[13] The number of cwear days per year varies approximatewy between 80 and 125, and de typicaw temperature variation drough de year are 18–27 °C.[14]

Cwimate change made it 175 times more wikewy dat de surface waters of de Coraw Sea wouwd reach de record-breaking temperatures March 2016 dat bweached reefs, modewing anawysis showed.[15]

Winds in de Coraw Sea can be cwassified by season, wongitude and watitude. Soudeasterwy trade winds dominate drough aww sea areas and aww seasons, especiawwy between 20°S and 25°S, west of de meridian of 155°E. However, between September and December dey change to norderwy and nordwesterwy winds in dis region, and de direction is mostwy soudwestern in May–August. West of 155°E, gawes are common between January and August and are wess freqwent in September–December.[16]

In January, de nordwest monsoon may occur between de parawwews of 15°S and 20°S, west of de 150°E meridian, uh-hah-hah-hah. Gawes are rare in dis region most of de year except for June–August, when strong soudeasterwy winds occur a few days per monf.[16]

The soudeasterwy trades are awso strong norf of 15°S between March and November. They weaken and often change to westerwy winds in December and to norderwy and nordwesterwy winds in January
and February.[16]

The Austrawian shore of de Coraw Sea is mostwy composed of sand. The GBR is too far away to provide significant coraw deposits, but it effectivewy screens de coast from de ocean waves. As a resuwt, most wand vegetation spreads down to de sea,[17] and de coastaw waters are rich in underwater vegetation, such as green awgae.[18] The most common genera of seagrasses are Hawophiwa and Hawoduwe.[19]

The iswands of de GBR contain more dan 2,000 pwant species, and dree of dese are endemic. The nordern iswands have 300–350 pwant species which tend to be woody, whereas de soudern iswands have 200 which are more herbaceous; de Whitsunday region is de most diverse, supporting 1,141 species. The pwants are spread by birds.[20]

Crown-of-dorns starfish (Acandaster pwanci) is de major predator of de reefs, as it preys upon coraw powyps by cwimbing onto dem, extruding its stomach over dem, and reweasing digestive enzymes to absorb de wiqwefied tissue. An individuaw aduwt can eat up to 6 m2 of reef per year.[26] In 2000, an outbreak[27] of crown-of-dorns starfish contributed to a woss of 66% of wive coraw cover on sampwed reefs.[28] Changes in water qwawity and overfishing of naturaw predators, such as de Giant Triton, may have contributed to an increase in de number of crown-of-dorns starfish.[29]

More dan 200 species of birds (incwuding 22 species of seabirds and 32 species of shorebirds) visit, nest or roost on de iswands and reefs,[33] incwuding de white-bewwied sea eagwe and roseate tern.[21] Most nesting sites are on iswands in de nordern and soudern regions of de GBR, wif 1.4–1.7 miwwion birds using de sites to breed.[34][35]

Seventeen species of sea snake, incwuding Laticauda cowubrina[36] (pictured), wive on de GBR in warm waters up to 50 metres (160 ft) deep and are more common in de soudern dan in de nordern section; none of dem are endemic or endangered.[37] The venom of many of dese snakes is highwy toxic; for exampwe, Aipysurus duboisii is regarded as de worwd's most venomous sea snake.[38][39][40]

The coastaw areas of de Coraw Sea were popuwated at weast 40,000 years ago by prehistoric peopwe descending drough de nordern iswands. Those Aboriginaw tribes have been dispersed and nowadays onwy about 70 groups wive in de area around de GBR.[48]

Navigation has wong been a traditionaw human activity on de Coraw Sea and dere are 10 major ports on de Queenswand coast awone. More dan 3,500 ships operated in dis area in 2007, making over 9,700 voyages dat transported coaw, sugar, iron ore, timber, oiw, chemicaws, cattwe and oder goods.[49] The abundance of coraw reefs hinders shipping traffic, and about 50–60 accidents per year were reported between 1990 and 2007 in de GBR awone.[50]

Oder economic activities in de sea incwude fishing and expworation of petroweum deposits in de Guwf of Papua.[2] The sea is awso a popuwar tourism destination, uh-hah-hah-hah. In 2006–2007, tourism on de GBR contributed A$5.1 biwwion to de Austrawian economy.[51] The tourism is mostwy foreign or from remote parts of Austrawia, wif a wocaw contribution of about A$153 miwwion, uh-hah-hah-hah. In particuwar, about 14.6 miwwion visits were made to de Coraw Sea reefs by de Queenswand residents over 12 monds in 2008.[52] Growing concerns over de environmentaw effects of tourism resuwted in estabwishment in 1975 of de Great Barrier Reef Marine Park. There are awso smawwer state and nationaw parks. In 1981, de Great Barrier Reef was decwared a Worwd Heritage Site by UNESCO.[9] From de middwe of 2004, approximatewy one-dird of de GBR Marine Park is protected from species removaw of any kind, incwuding fishing, widout written permission, uh-hah-hah-hah.[53]

It was suggested in 1923 dat de Great Barrier Reef contains a major oiw reservoir. After de Commonweawf Petroweum Search Subsidies Act of 1957, hydrocarbon expworation increased in Queenswand, incwuding a weww driwwed at Wreck Iswand in de soudern Great Barrier Reef in 1959.[54] In de 1960s, driwwing for oiw and gas was investigated droughout de Great Barrier Reef,[55][56] in de Torres Strait, awong "de eastern seaboard of Cape York to Princess Charwotte Bay" and awong de coast from Cooktown to Fraser Iswand. In de wate 1960s, more expworatory oiw wewws were driwwed near Wreck Iswand in de Capricorn Channew, and near Darnwey Iswand in de Torres Strait, but wif no resuwts.[54] In de 1970s, responding to concern about oiw spiwws, de Austrawian government forbade petroweum driwwing on de GBR.[57][58] Yet oiw spiwws due to shipping accidents are stiww a dreat to environment, wif a totaw of 282 spiwws between 1987 and 2002.[59]

Shen Neng 1 aground on de Great Barrier Reef on 5 Apriw 2010

Queenswand has severaw major urban centres on de coast incwuding Cairns, Townsviwwe, Mackay, Rockhampton, Bundaberg, Sunshine Coast and de industriaw city of Gwadstone, which inevitabwy contaminate de sea. About dirty rivers and hundreds of smaww streams add continentaw water, which contains sediments, pesticides and industriaw waste.[60] Runoff is especiawwy concerning in de region souf of Cairns, as it may receive up to 4200 mm of rain per year.[14] About 90% of sea contamination originates from wand farming activities.[61] The area is continuouswy urbanising, so dat de popuwation is expected to increase by 40% by 2026. As a resuwt, 70–90% of de coastaw wetwands has been wost over de past decades, and many remaining fwora species are endangered.[62]

On 3 Apriw 2010, de Chinese ship Shen Neng 1 carrying 950 tonnes of oiw, ran aground east of Rockhampton in Centraw Queenswand, Austrawia,[63] causing de 2010 Great Barrier Reef oiw spiww and infwicting de wargest damage to de GBR and de Coraw Sea so far.[64] The scarred area was roughwy 3 km (1.9 mi) wong and 250 m (820 ft) wide,[65] and some parts of it have become compwetewy devoid of marine wife. There are concerns dat dere couwd be considerabwe wong-term damage and it wiww take 10 to 20 years for de reef to recover.[66] By 13 Apriw 2010, oiw tar bawws were washing up on de beaches of Norf West Iswand, a significant bird rookery and turtwe nesting cowony.[64]

A group of 10 environment NGOs have come togeder as a coawition cawwed de Protect our Coraw Sea campaign, asking de government to create a very warge highwy protected Coraw Sea Marine Park.[67] In November 2011 de Austrawian government announced dat a 989,842 sqware kiwometres (382,180 sq mi) protected area was pwanned and pending approvaw.[68]

^"Coastaw water qwawity"(PDF). The State of de Environment Report Queenswand 2003. Environment Protection Agency Queenswand. 2003. Archived from de originaw(PDF) on 25 March 2009. Retrieved 2007-06-07.